The present invention relates generally to gas turbine engines and more particularly to a cooling circuit for a platform of a turbine airfoil.
Turbine blades in a gas turbine engine extend outwardly from a turbine blade platform. In operation, the turbine blades are routinely exposed to temperatures well above their material limits. In existing engines, air from the compressor section of the turbine engine is used to cool the blade material. This cooling air is fed to the blade through a series of rotor cavities underneath the blade platform. The cooling air is then injected into the hot mainstream flow through openings in the sealing area.
Without sufficient cooling of the platform, the platform walls may experience creep deformation. High temperature gradients in the platform may result in thermal-mechanical fatigue. Additionally, the high temperatures can cause oxidation of the platforms.